Overview
ISO 20701:2017 specifies a standardized method for testing the colour fastness to saliva of all types of leather, regardless of the leather coloring process used. This international standard uses an artificial saliva solution to simulate exposure conditions in the mouth, assessing whether colorants from leather may migrate onto oral mucous membranes. The method is critical for ensuring leather products remain safe and aesthetically durable, especially in applications involving close contact with the mouth.
Developed by ISO in collaboration with the International Union of Leather Technologists and Chemists Societies (IULTCS), ISO 20701:2017 provides manufacturers, testers, and quality assurance professionals a reliable, reproducible procedure aligned with established fastness testing principles.
Key Topics
- Scope: Applicable to all leather types and finishing methods for determining color fastness to saliva.
- Artificial Saliva Solution: A precisely composed salt solution replicates the chemical environment of natural saliva (pH 6.8 ± 0.1). Key components include magnesium chloride, calcium chloride, potassium phosphates, and sodium chloride.
- Test Procedure:
- Filter paper soaked in artificial saliva is placed on the leather surface and maintained at 37 ± 2 °C for 120 ± 5 minutes.
- Following the exposure, both leather and filter paper are dried and visually or instrumentally evaluated for color change and staining.
- Evaluation Standards: Color changes are assessed using grey scales according to ISO 105-A02 for leather color change and ISO 105-A03 for staining on paper. Optionally, instrumental methods per ISO 105-A04 and ISO 105-A05 can be applied.
- Precision: Visual evaluation precision is ± 0.5 grey-scale units, ensuring consistent result interpretation.
- Test Reporting: Reports include the leather type, surface tested, grey-scale ratings for staining and color change, and any deviations from standard procedures.
Applications
ISO 20701:2017 is essential for industries where leather products may come into contact with the mouth or mucous membranes, including:
- Footwear Manufacture: Ensuring linings or straps do not transfer dyes during use.
- Children’s Leather Goods: Pacifier holders, teething rings, or toys requiring strong safety guidelines.
- Leather Accessories: Wallets, watch straps, gloves, and other wearable goods with prolonged skin contact.
- Automotive and Furniture Upholstery: Verifying color fastness under conditions simulating human contact.
- Quality Control and Compliance Testing: Meeting regulatory demands for product safety and chemical migration limits.
This testing supports product safety assurance, helps avoid consumer complaints regarding staining or dye transfer, and enhances brand reputation by ensuring leather finishes remain durable and non-toxic.
Related Standards
ISO 20701:2017 references and complements several related standards for a comprehensive approach to color fastness and leather testing, including:
- ISO 105 Series: General color fastness tests, including fastness to washing, rubbing, and light exposure.
- ISO 2418: Leather sampling guidelines to secure representative specimens for testing.
- ISO 3696: Quality requirements for water used in analytical laboratory applications.
- EN 15987: Terminology and key definitions for leather trade.
- DIN 53160-1: German standard for color fastness testing with artificial saliva, serving as a related methodology reference.
By integrating ISO 20701:2017 with these standards, organizations can ensure robust quality control and regulatory compliance in leather product manufacturing and testing.
Keywords: ISO 20701, colour fastness to saliva, leather testing, artificial saliva solution, leather color fastness, ISO leather standards, leather quality control, leather dye migration, leather safety testing, IULTCS.